A particular class of lubricant composition can be characterized as liquid lubricants having at least two distinct liquid phases. Often, these types of lubricants are considered as dispersions, although they are also referred to as emulsions. These types of lubricants are readily identified as having a relatively small quantity of the discontinuous phase, which is comprised of an oil type component and dispersed throughout the continuous oil base oil phase. Since an oil type composition is dispersed through another oil type composition, these lubricants are also referred to as oil-in-oil emulsions.
Oil-in-oil emulsions can provide substantial wear protection, yet be lower in viscosity relative to standard mineral oil type blended lubricants. Such lubricants can be useful in many applications and are desirable for their superior properties related to low viscosities, improved film thickness, and better lubricating performance.
U.S. Pat. No. 6,972,275, Forbus, discloses an oil-in-oil emulsion type of lubricant composition. The particular lubricant composition has a continuous phase of a carrier fluid comprised of polyalphaolefins and alkylated aromatics, and a discontinuous phase of a higher viscosity fluid. The carrier fluid and the high viscosity fluid are substantially immiscible and together form a relatively stable emulsion.
Two phase lubricants such as oil-in-oil emulsions have very good potential for numerous commercial applications. However, additional improvements in overall lubricant quality and performance are desired. Additional wear protection and lower drag are examples of qualities in which improvements are being sought.